The switch of the present invention is of the family of switches having application in timing apparatus, as for example, apparatus adapted for use in the control of a conditioning system. The conditioning system may have a 12-hour but preferably a 24-hour timed cycle within which two or more members will each complete one excursion to actuate a switch at times which are preset. Each member is comprised of a pin which rotates about an axis and into contact with an inclined surface formed on an element carried by a switch actuator. The switch is a single pole, double throw switch having a center arm which undergoes snap action from one to another stable position of contact with an outer arm. The switch actuator is pivotally mounted and operatively connected to the center arm by a loading means. When the switch actuator following movement of a pin along the inclined surface of the element moves through an over center position the center arm will undergo the aforementioned snap action.
As should be appreciated, these devices wherein a member, such as the aforementioned pin completes an excursion throughout a 12 or 24-hour cycle are extremely slow in action. This slowness of action has been found to introduce a noticeable disadvantage in the operation of switches of this type. Thus, the center arm and contact slowly withdraws from its contact with an outer arm as the pin follows the inclined surface with the result that only extremely light contact pressure which reduces to zero substantially prior to actuation from one stable position to the other is maintained. This condition has been found exceptionally undesirable in applications of the prior art switches in the timing of an operation in an environmental control system for the purpose of providing a variety of operating conditions such as temperature during certain periods of time. To this end, in some situations it has been found that there may be an interruption in contact for as long as several minutes time. A further disadvantage of a slow withdrawal of one contact from another contact, depending upon the voltage characteristics of the system results from arcing and the deterioration of the contacts.